MAGNETIC AND ELECTRIC

When a magnetic field changes around a wire or coil, it creates an electric current. This is electromagnetic induction, discovered by Faraday. Think of it like this: moving a magnet near a coil of wire forces electrons to move, generating electricity without any battery needed.

Self-induction happens when a coil's own changing current creates a magnetic field that opposes the original change. Mutual induction occurs between two separate coils—when current changes in one coil, it induces current in a nearby coil.

A transformer uses mutual induction brilliantly. The National Grid in Nigeria steps down high voltage electricity from power stations to safe levels for homes using transformers. The primary coil receives alternating current, creating a changing magnetic field that induces current in the secondary coil. The voltage depends on the ratio of wire turns in each coil.